Driving mechanism for self-propelled vehicles.



No, 768,636, PATENTED AUG. so, 1904. E. THOMSON & H. LEMP.

DRIVING MECHANISM POR SELF PROPELLED VEHICLES.

APPLICATION FILED 001222, 1902.

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lnver'rbors: EllhuTl-womson,

b3 Hermann Lem p,

@M www@ No. 768,636. PATENTED AUG. 30, 1904. E. THOMSON & H. LEMP.

DRIVING MECHANISM EUR SELFI PROPELLED VEHICLES.

APPLICATION HLM) ocmzz, 1902.

N0 MODEL. 3 SHEETS-SHEET 2.

` i/Lnesses: InvehCoY's: /W 5% Elihuhomsor'l,

No. 768,636. PATENTBD AUG. 30, 1904. I

` v E. THOMSON & H. LEMP. DRIVING MEGHANIS'M FOR SELF VPROPELLEDVEHICLES APPLICATION FILED 00T.22, 1902.

No MODEL.

a SHEETS-SHEET a.

5 Y n o O .C vm s c ,7V/VI, te w/f-.I` f. D VI.1..( .|17 ...n nh@ v Il..N wm., m. lili |1|- -t il i l. 11,1, lljlllllrlli lrllllllllllllliljllli @auf Patented August 30, 1904.

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ArnNr ELIHU THOMSON, OE SVAMPSCOTT, AND HERMANN LEMP, OF LYNN,MASSACHUSETTS, ASSIGNORS, BY DIRECT AN l) MESNE ASSIGNMENTS, TO GENERALELECTRIC COMPANY, A CORPORATTON OF NEW YORK.

DRIVING IVIEICHANISIVI FOR SLF-PROPELLED VEHICLES.

SPECIFICATION forming part of Letters Patent No. 768,636, dated August30, 1904.

Application filed October 22, 1902. Serial No. 128,283. (No model.)

To rr/Z 'Ll/71,0771, it 12m/y concern:

Be it known that we,ELIHU THOMSON, residing at Swampscott, and HERMANNLEMP, residing at Lynn, county of Essex, and State of Massachusetts,citizens of the United States, h ave invented certain new and usefulImprovements in Driving Mechanism for Self-Propelled Vehicles, of whichthe following is a specification.

The present invention relates to driving mechanism for self-propelledvehicles, and more especiallyY to those wherein worm-gearing forms orenters into the construction between the motor and the driving' wheel orwheels.

The object of the invention is to improve and simplify the constructionof the mechanism, whereby its life may be increased and the partsrendered accessible for inspection or repairs.

Other features of novelty will be referred to specifically hereinafter.

For a consideration of what we consider to be novel and our inventionattention is called to the specification and claims appended thereto.

In the accompanying' drawings, which illustrate one embodiment of ourinvention, Figure 1 is a side elevation of a vehicle. Eig. 2 is a planview thereof with the body removed. Eig. 3 is an enlarged longitudinalsection of the intermediate driving-shaft and worm. Fig. et is anenlarged longitudinal section of the rear axle and differential gearing,and Fig. 5 is a perspective view of a roller for the axle-bearing.

1 represents the vehicle-body, which is provided with a suitable frame2. The vehicle illustrated is provided with two seats 3; but the numbercan be variedv to suit the requirements. The vehicle is under thecontrol of the reversing' device 4 and the throttle-lever 5. Thesteering-wheels are mounted on stubaxles 6, which are connected by therods in the usual manner with the steering lever or handle. The body issupported above the axles by suitable springs 7. In the presentillustration four springs are shown; but the number and arrangement canbe varied to suit the conditions of operation.

Mounted below the vehicle-body at any convenient point, but preferablyin the forward part away from the boiler, is a motive device S. In thepresent instance it is a steam-engine; but any other form of motor canbe employed without departing' from our invention. Extendingtransversely with respect to the body is a support 9, and to saidsupport is bolted' a bearing 10 for the main shaft 11 of the motor. Thesupport 9 also sustains one end of the motor, the other end beingsupported by the tube or rod 12. Detachably secured to the end of thedriving-shaft is a fork 13, to which is pivotally secured a piece 14..The piece 15 forms the connection between the driving and driven shaftsand is pivotally secured to the fork 16, the latter being rigidlysecured to the driven or intermediate shaft 17. In other words, thepiece 15 is pivotally secured by bolts to the two forks and forms thepower-transmitting medium between them. The forks and connecting partsconstitute a universal connection between the driving-shaft of the motorand the intermediate driving-shaft 17. As shown, the driven shaft ishorizontal; but it can be inclined, if desired. We consider it best toso arrange the parts that the shaft is horizontal when the vehicle isloaded. It is necessary to employ a universal connection between theparts of the shaft in order that the engine may move up and down freelywith respect to the driven axle without causing the parts to bind orcramp. It also enables us to mount the motor in a horizontal positionwith the axle-driving gear in a plane above or below that of thedriving-shaft. Again, such a connection permits of the parts'beingassembled without'extraordinary care being taken in alining. This latterfeature is important, because the average repairer is compelled to workwithout the gages commonly used in factories for insuring the properposition and relation of the parts with respect to each other. Theuniversal connection must be arranged to move with the vehicle-body andgg fies,

universal joint, two distance bars or tubes 1S 5 are employed.

rlhcsc bars are united one end with the rear axle and at the other endare l pivotally secured to hangers i9,the latter being' secured to thebody or to some portion of its frame. From Fig'. 2 it will be noted thatthe dotted line 2l) passes through the centers of the pivots of thedistance-bars 13 and also through the pivot or pivots of the universalcoupling, showing them to be in line. Furthermore, the center line ofpivots is arranged in the saine horizontal plane as that of thedrivingshaft. B v reason of this construction entire freedom of movementis obtained.

The driving-wheels 21 are located at the rear of the vehicle; but theymay be located otherwise, if desired. The wheels are rigidly fastened tothe divided axles 22 23, the former being solid in the present instanceand the latter tubular. There is a limited amount of movement betweenthe axles toward or away from each other. due to the elasticity of thesprings. The aXle 22 is provided with end nuts 25 to hold the wheels inplace and prevent the parts of the axle from separating'. Thebody-springs are provided with supports 2t. which rest on the axle. Theleaves of the spring are held together and secured to the support 26 bythe clamp 27 and by the bolt 23, which passes through them. rfhe support2G is bored out to receive the hard-steel lining 28 that surrounds thesleeve 29, and between the two are a number of hard-steel rollers 30,made in the form of a coiled spring, Fig. The bearings are provided foreach rear spring and take the weight of the vehicle-body and partscarried thereby. At the ends of the rollers are provided pieces 31 toprevent endwise movement. rlhe side of the bearing-support nearer thewheel has a hub-like extension 32, which carries the stationary elementof the brake mechanism. Suflicient clearance is provided between theaxle-sleeve 23 and the extension to prevent the parts from rubbing. 'lhis arrangementdispenses with the necessity of lubrication at thatpoint. The stationary element 33 of the brake is clamped to theextension by the inclined set-screw 34. Only one of these set-screws isshown; but it is to be understood that more can be used, if desired.Extending from the brake element 33 is lug 35, which engages the support26 and assists in holding' the parts in place. On the lower part of thesupport for the spring' are formed ears 36, and mounted therein is abrake-actuator 3T, which spreads or expands the stationary cylindricalbrake element and causes it to grip the brake-drum 33, carried b v a Tothe actuator is connected driving-wheel.

an arm 39, and this in turn is connected by a rod orl equivalent devicewith a brake-actuator under the cont-rol of the operator. From theforegoing it will be seen that the support 26 not only forms a cradle orsupport for the body-spring, but it also carries a part of the brakemechanism and a roller-bearing'.

The power of the motor is transmitted to the driving-wheels bymeans of aworm and differential gearing, the latter permitting one wheel to moveat a different rate of speed than the other, as in turning corners. 40represents a bevel-gear which is rigidly secured to the axleesleeve 23,and 4l represents a second bevel-gear facingl the lirst and which isrigidly secured to the axle 22. The adjacent faces of the hubs of thegears are finished, and situated between them and acting as a spacer isthe hub of the Worm-wheel 42. Situated between the gears 40 and 41 in amanner to engage the teeth on both and carried by the worm-Wheel arepinions 43. In Fig's. 3 and 4 two pinions are shown: but the number canbe varied, if desired. lt is preferable to employ at least two in orderto better distribute the strains. Surrounding the pinions and sleeved onthe axle 22 is a wormwheel 42, which meshes with the worm 44, that isdriven by the main driving-shaft of the engine through the medium of theuniversal connection and the intermediate shaft 17. The relation betweenthe teeth on the drivingworm and on the worm-wheel is such that the wormcan drive the wheel when power is applied thereto or the wheel canimpart rotary motion to the worm when the vehicle is coasting. By reasonof this construction we are enabled to dispense with all clutches andtheir operating mechanism, which would otherwise be necessary.

rlhe pinions 43 are mounted on a support 45, which has as manyradially-extending arms there are pinions, each of said armsconstituting a pivot for a pinion. The support is boredl centrally andis sleeved on the hub 46 of the worm-wheel 42. A Hange on one side ofthe hub prevents it from slipping laterally, and the hub of theleft-hand bevel-gear 41 prevents it from moving in the oppositedirection. The pinions are held against radial movement by the shoulders47 and the nuts and. washers 48. The web of the wormwheel 42 is providedwith as many openings asthere are pinions, as is clearly shown in Fig.3. By reason of the construction described it is possible to arrange thepivots for the pinions so that their centers coincide with the centralplane of the worm-wheel without boring through the teeth of the worm,which is the usual practice. When the latter is followed, the teeth haveto be plugged afterward, and the results are far from satisfactory.

The right-hand beveled gear 40 is provided with an elongated hub and isrigidly secured to the wheel-carrying sleeve 23 by the lcy 5t).

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described.

vpreviously described.

The right-hand driving-Wheel is secured to the same sleeve by the key51. (Shown in elevation.) The wheel v52 has an elongated hub whichterminates in a screw-threaded end on one side and in a brake-drum 38 onthe other. The sleeve 23 is provided with a shoulder 53 at a pointbetween the spring-carrying support and the differential gearing, andseated on this shoulder is a collar 5-1, which is prevented from turningby a pin. Between the collar and the support is a wearplate or washer55. Between thenut 25 and therighthand end of the sleeve 23 and the hubis a collar 56, and by changing the thickness of this lcollarcompensation can be had for the wearing of the parts. rlhe end of thehub is closed by a detachable screw-threaded cap 57.

The left-hand beveled driving-gear 41 is secured to the shaft or axle 22by the key 58, and the hub is elongated somewhat to form a part of abearing. Mounted on the aXle and secured thereto by the right-hand endof the key 59 is a sleeve 60, which is of the same eX- ternal diameteras the sleeve 23. The object in using this sleeve is to permit the useof interchangeable bearings on the right and left hand sides of thevehicle. In other words, it forms a lining. The end of the sleeveengages with a shoulder or collar formed on the shaft, and the parts areprevented from moving longitudinally in the manner previously Thearrangement of the brake and thespring-support is also the same as thatLubricant is supplied to the bearings by the cups 6l. The key 59 inaddition to holding the sleeve 60 secures the wheel to the part 22 ofthe axle.

Each-of the elongated hubs of the bevelgears forms a part of aroller-bearing, the other part being carried by the gear-casing itself.Between the bearings and the fianges of the gears are wear-plates 62,which also serve to prevent lateral movement of the gearcase withrespect to the gears.

The gears are inclosed in a casing made up of separable parts. ln thepresent instance the casing is made of two principal parts 62 and 63.The parts make a snug titwith the elements of the axle and are heldtogether by bolts 64. which pass through lugs formed on the sidethereof. The line of division between the parts is in a plane parallelwith that of the intermediate driving-shaft'l7. The end of the shaft issupported in a bearing carried by a detachable screw-threaded piece 65.Mounted in the piece 65 and at the end of the drivingshaft is aroller-bearing 66 of anysuitable construction, and between thebearingand the end of the worm is a roller thrust-bearing 67. The wormcan be removed from its shaft by removing the plugI 65 and rotating theshaft '17. The worm being' secured to the shaft by a spline will movelongitudinallythereon. In the rear of the gear-casing and at a pointreadily accessible is a detachable screw-threaded plug 68 by means ofwhich lubricant can be introduced into the casing. Situated just abovethe plug and secured to the casing by screws is a plate 69, whichprevents `the screw-threaded piece 66 from turning when the parts are inservice. As will 4be seen, the gearing is entirely inclosed wit-hinacasing which prevents access of dust and dirt, and by fillingl thecasing with a certain amount of lubricant the parts will runquietly andbe well lubricated. The sleeve 23, opening into the casing, will alsoreceive a certain amount of lubricant. wie have found that where thereduction between the driving-shaft and the worm-wheel is from about oneto five up to about one to eight that very satisfactory results can beobtained. In the present instance the teeth of the worin-wheel have alead of about three inches. Both the reduction and the lead can ofcourse be varied somewhat to suit the requirements; but the worm-wheelis preferably so arranged that it can drive the worm. f

In order to support the gear-casing and prevent the parts from beingunduly strained under the action'of the driving-worm, a suitable frameis provided. In the present form of our invention the frame forpreventing the gear-casing from turning comprises a single support ortube; but it is to be understood that this can be modified withoutdeparting from our invention. The essential feature is to provide ameans for preventing the gearcasing and the auxiliary or intermediatedriving-shaft bearing from turning' and to lconnect said means to thevehicle body by a pivotal connection. The frame tube or support 70 isrigidlysecured in a socket formed in the gear-casing at one end and atthe op-vv posite end is provided with a bearing which engages with theintermediate shaft 17.

The socket 7l is provided with a shoulder to receivethe thrust-collar 72and rollers 73.

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By reason of the' thrust-collars and rollers located at opposite ends ofthe worm all longitudinal movement thereof is prevented,"'l`l1e worm endof shaft 17 is provided with a rollerbearing 7 3. that is supported bythe socket.

The bearing is held in place by the thrustrings 72 and a collar formedon the shaft. The end of the supporting-frame tube 70, which is nearerthe motor, yis provided with a socket 74, thatis rigidly attachedthereto. In

this socket is mounted a roller-bearing 75,

having acage 76 for retaining the rollers. The socket is linedv with ahardened-steel shell 77, forming a bearing-surface. Secured to the endof the shaft 17 is the fork 16, which has an elongated hub. andsurrounding this hub is a hardened sleeve 73, having a cupshaped liangeat its outer end. Between the flange and the rollers is a packing offelt or similar material 79to preventlubricant from Working' out anddirt from working into the bearing.

From the construction described it is evident that any tendency for thegear-casing and the bearing to revolve around the rear axle, d uc to theload on the vehicle, is resisted by the support 70, and that since thebearing at its outer end is carried by the shaft 17 all of the strainsof transmission are carried by the latter. le prefer to place the socket'74: and its bearing at some considerable distance from the gear-casing,because the effective leverage exerted by the casing on its supportdecreases as the length of the support increases. lVe wish it to beunderstood, however, that our invention is not limited to placing thesocket and its bearing at lany specified point on the shaft. It will benoted that supporting the bearing on the shaft 17 gives to it the samerelation with respect to the motor that the'shaft has-that is to say, itwill not bind when the vehicle-bod y moves up and down, neither will itbind if the parts are not accurately alined because of the universalcoupling. To put the matter in a different way, the advantages of auniveral joint are provided for the bearing, yet only a single joint isprovided for both. To put the matter in a still different way, thesocket and bearing are supported by a universal coupling from thespring-supported vehicle-body through the medium of the parts 17, whichalso forms an element in the driving mechanism, thereby performing twofunctions with the same piece.

1n accordance with the provisions of the patent statutes we havedescribed the principle of operation of our invention. together with theapparatus which we now consider to represent the best embodimentthereof; but we desire to have it understood that the apparatus shown isonly illhistrative and that the invention can be carried out by othermeans.

W' hat we claim as new, and desire to secure by Letters Patent of theUnited States, is4

1. 1n combination, a vehicle-body, axles therefor which are movabletoward and away from each other to a limited extent, springs which unitethe body with the axles, a gearwheel mounted on one axle, a second gearengaging therewith, a motor mounted on the spring-supported body, auniversal coupling between the motor and the second gear, a tube whichsurrounds and supports the shaft ofthe motor, and a distance-bar forholding the motor at a fixed distance from the axle carrying thefirst-named gear.

2. 1n a vehicle, the combination of a body, a motor, an axle, adriving-shaft, worm-gearing between the axle and shaft, a casi ngtherefor, a tube for preventing the casing from turning, and a bearingfor one end of the tube which engages with the shaft.

3. VIn a vehicle, the combination of a body,

a motor mounted thereon, an axle, a worm- .gagement with the wheel, auniversal coupling between the motor and the shaft, and a support forthe bearing which engages with the said coupling.

11. ln com bination,aspring-supported body, a motor mounted thereonhaving a drivingshaft, an intermediate shaft, a fiexible couplingbetween the shafts, a driven shaft, a worm-gearing between theintermediate and the driven shaft, a distancebar having the same centersof motion as the coupling and the driven shaft, a casing for thegearing, a bearing for one of the shafts that is carried by the casing,and means for preventing the casing from rotating.

5. In a vehicle, the combination of a springsupported body,driving-wheels and an axle, a motor mounted on the body, gearingconnected to the wheels, a bearing for the driving-gear which is sleevedon the axle, a driving connection between the motor and the drivinggear, a longitudinally extending frame surrounding the shaft forpreventing the bearing from turning around the axle, a universalconnection between the frame and the vehicle-body, and a pair ofdistance-bars whose centers of motion coincide with that of theuniversal connection.

6. In a vehicle, the combination of a body, a driving and driven axle,springs which are attached to the body and the axles, a motor mounted onthe body, gearing between the axle and motor, a flexible couplingincluded in said gearing, a frame for holding' the gearing in mesh thatis supported by the body, and a flexible coupling in said frame.

7. 1n a vehicle, the combination of aspringsupported body, a motormounted thereon, a driving-axle, springs secured thereto and to thebody, agear-case sleeved on said axle, gearing within the case, a framewhich is supported by the body for preventing the case from turning, auniversal connection in said frame, and distance-bars which preserve therelation between the. motor and the drivingaxle.

8, In combination, a vehicle-body, a motor mounted thereon, an axle,worm-gearing, a shaft foi' driving the worm, a tube which surrounds' theshaft for preventing the worm from rotating and which is partiallysupported by the said shaft, anda flexible coupling between the shaftand the motor.

9. In avehicle, the combination of aframe, a body mounted thereon, adriving and a driven axle, a motor mounted on the frame, springs betweenthe frame and the axles, a gear mounted on one of the axles, a shaft fortransmitting motion from the motor to the axle, a universal connectionfor said shaft, a bearing for the axle end of the shaft, and anelongated frame for preventing the bearing from rotating around the axlewhich is supported by the shaft at a point adjacent to the coupling.

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10. In combination, a vehicle-body, an axle, a motor, worm-drivinggearing, a shaft for transmitting motion from the motor to the gearing,and a gear-casing which is sleeved on the axle, a tube which surroundsthe shaft and is sleeved thereon for preventing the casing from turning,and a distance-bar Jfor maintaining a fixed separation between the motorand the axle.

11. In avehicle, the combination of a body, a motor mounted thereon withits drivingshaft extending longitudinally of the body, an axle, aworm-wheel on the axle, an intermediate shaft which forms a continuationof the driving-shaft, a flexible coupling between the two shafts, a wormthat is ,mounted on the intermediate shaft and engages with the gear,the pitch of the worm and gear being such that the gear can drive theworm, and a pair of adjustable distance-bars situated on opposite sidesof the driving-shaft and secured to the body for preserving the relationbetween the motor and axle.

12. In a vehicle, the combination of a springsupported body, adriving-axle, gearing on the axle, a motor, a pair of transverseframerods to which the motor is secured, a case for the gearing which'issleeved on the axle, and a frame which is connected to the case and ispivotally supported by the body.

13. In a vehicle,the combination of a spring'- supported body, a motormounted thereon, a driving-axle, a worm-wheel mounted on the axle, ashaft which is provided with a worm and extends from the motor to thewormwheel, a case which surrounds the worm-gearing and carries a bearingfor the shaft, a frame for preventing the case from rotating, a pivotalconnection between the frame and the vehicle-body, and a pair ofdistance-bars that are pivotally secured to the body of thedriving-axle.

14. In a vehicle,thecombination of a springsupported body, a motormounted thereon, an axle, a driving connection between the motor andaxle, a universal joint in said connection, a bearing for the drivingconnection, a tube which surrounds the connection and is carried by thespring-supported body for preventing the bearing from turning',distancerods extending between the axle and the body, and pivotalconnections between the rodsand the body, whose centers of motioncoincide with that of the universal joint.

15. In a vehicle, the combination of a springsupported body, a motormounted thereon, a gear which is carried by the axle and is driven bythe motor, a universal coupling between the motor and gear, a gear-case,and a fr ame supported by the universal coupling which prevents thegear-casing from rotating.

16. In a vehicle,the combination of a springsupported body, a motormounted thereon, a gear which is carried by the axle and is driven bythe motor, a gear-case, a frame which is -the driving-gear, a dividedcasing which surrounds the gears and contains a bearing for the worm,and a motor that is connected to the worm and is mounted on thespring-supported body.

18. In a vehicle,the combination of a springsupported body, a dividedaxle, a worm-wheel mounted thereon, a worm meshing therewith, a shaftfor driving the worm, a bearing for the shaft, differential gearingbetween the ends of the axle, an inclosing case for the gears, having asocket, and a tubular frame which is seated in the socket and sleeve onthe shaft for preventing the bearing from turning.

19. In combination, a worm-wheel, a worm meshing therewith, adriving-shaft therefor, a bearingl for the shaft, a casing whichsurrounds the wheel and worm and supports the bearing, a frame-tubewhich lits intoa socket formed in the casing, and a bearing which issleeved on the shaft and supports the end of the frame-tube.

20. In combination, a springsupported body, a divided axle, a worm-wheelmounted thereon, a worm meshing therewith, thrustbearings for the worm,a support for the bearings, bearings between the support and the axle,dierential gearing between the ends of the shaft, and a frame which issupported by the body for preventing the support from turning.

21. In combination, a spring-supported body, a divided axle, a pair ofoppositely-disposed bevel-gears, a worm-wheel situated between thegears, pinions which mesh with the gears and are carried by the wheel, aworm which engages with the wheel, a casing which supports the worm, abearing for supporting the casing on the axle, a frame which issupported by the body for preventing the casing from turning, and auniversal coupling in said frame.

2Q. In combination, a divided axle, a sleeve mounted thereon, a pair ofbevel-gears one of which is connected to the axle and the other to theshaft, pinions connecting the gears, a worm-wheel which surrounds thegears and carries the pinions, a worm, a casing, a bearing for the wormwhich Vis supported by the casing, a frame for preventing the casingfrom rotating, and a universal coupling in said frame.

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Vgears each having an elongated hub, a pinion 23. In a vehicle, thecombination of an axle, a sleeve mounted thereon, a pair ot' bevel gearsone of which is connected to the axle and the other to the shaft,pinions for connecting the gears, a worm-wheel which surrounds andcarries the pinions, a worm, a casing, a bearing' for the worm which issupported by the casing', a 'frame for preventing the casing fromrotating', bearings for the casing which support it on the axle, aspringsupported body, and a pair of distance-bars 1 which are pi votallyconnected to the bod y and to the axle.

24. In combination, an axle, a pair of bevelmeshing with both gears, aworm-wheel that carries the pinion, a worm, a casing which incloses theg'earing and is provided with a socket, bearings t'or the casing whichare supported by the gear-hubs, and a tube for preventing' the casingfrom turning', which is seated in the socket.

25. 1n combination, an axle, bcvelgears mounted thereon, a wheel whichis sleeved on J the axle between them, pinions which mesh with thegears, and a support for the pinions 1 which is sleeved on theworm-wheel.

26. ln combination, an axle, gears mounti ed thereon, pinions which meshwith the gears, a worm-wheel that is situated between the gears andA issleeved on the axle, a sup port for the pinion which is sleeved on thewheel, and aworm which meshes with the` wheel.

27. In combination, ashai't, a worm mounted thereon, a wheel meshing'with the worm, and a casing surrounding the worm and wheel which isprovided with an opening' in line with the shaft through which the wormcan be removed.

28. 1n combination, a shaft, a worm mounted thereon, a wheel meshingwith the worm, a casing surrounding the worm and wheel which is providedwith an opening in line with the shaft through which the worm can beremoved, and a cover which normally closes said opening'.

29. ln combination, a shaft, a worm mounted thereon, a wheel meshingwith the worm,

, a casing lsm'rounding the worm and wheel which is provided with anopening in line with the shat't through which the worm can be removed, acover which normally closes said opening', and a bearingvfor the shaftthat is carried by the cover.

30. In combination, ashaft, a worm mounted thereon, a wheel meshing withthe worm,

l a casing surrounding' the worm and wheel which is provided with anopening in line with the shaft through which the worm can be removed, ascrew-threaded plug which normally closes said opening, and parallelland thrust bearings which are carried by said plug'.

In witness whereof we have hereunto set our hands this 20th day ot'October, 1902.

ELIHU THOMSON. HERMANN LEMP.

lifitiiesses:

DUGALD MoKILLor, J om' A. McMANUs.

